Europe’s long-delayed flagship rocket is about to launch for the first time (2024)

Europe's Ariane 6 rocket is finally ready to fly, four years late but vital as ever for European governments backing the more than $4 billion project.

Set for liftoff from French Guiana, the new rocket will be Europe's flagship launcher for the next decade, providing rides to space for European science probes, navigation satellites, and military payloads. Ariane 6 also has a toehold in the commercial market, with a contract for 18 launches to deliver satellites to orbit for Amazon's Project Kuiper broadband network.

The first Ariane 6 rocket has a four-hour launch window opening at 2 pm EDT (18:00 UTC) Tuesday to depart the European-run Guiana Space Center in South America.

“Ariane 6 is Europe’s workhorse for guaranteed access to space," said Lucia Linares, head of space transportation strategy and institutional launches at the European Space Agency. "It is a true European public and industrial undertaking with the involvement of 13 European Space Agency member states and more than 600 companies across Europe.”

The launch comes a decade after officials settled on the basic design of the expendable Ariane 6 launcher, and nine years after the European Space Agency awarded a multibillion-dollar contract to a consortium of European companies to develop the continent's next big rocket.

The debut of Ariane 6 also comes almost exactly a year after the final flight of the Ariane 5 rocket, which notched 117 flights from 1996 through 2023. The Ariane 5, like the Ariane 4 and other Ariane rockets before it, was a market leader for launching large commercial communications satellites until SpaceX's Falcon 9 rocket took the top position in recent years.

ESA is overseeing the Ariane 6 demonstration flight before handing over commercial operations to Arianespace later this year. You can watch ESA's live broadcast of the inaugural Ariane 6 launch below.

High stakes

It hasn't been easy for Ariane 6 to reach this point. Inaugural flights of new rockets are risky, so ESA did not put a pricey payload on the first Ariane 6.

"About half of the inaugural flights do not go as planned," said Toni Tolker-Nielsen, ESA's director of space transportation, in a prelaunch press briefing. "I think we can do better with Ariane 6, but the 9th of July will confirm that for me.”

Asked about his mood and stress levels going into the maiden flight of Ariane 6, he replied he was about 96 percent confident.

"If it goes wrong, we’re going to do some investigations to find out what happened," Tolker-Nielsen said. "If it went badly, we’re going to correct it and we are going to do a second demonstration flight.”

The first flight of the Ariane 5 rocket didn't make it far from the launch pad on June 4, 1996. It lost control, broke apart, and exploded about 30 seconds after liftoff. An investigation found that the accident was caused by software code from the Ariane 4 rocket that engineers entered into the Ariane 5's guidance system. The explosion destroyed four ESA scientific satellites, resulting in a total loss of $370 million in 1996 dollars.

Lesson learned for Ariane 6.

"Everyone is aware of the issues linked to an inaugural flight, so everyone is aware of the risk of failure," said Franck Huiban, head of civil programs at ArianeGroup, Ariane 6's prime contractor.

If all goes according to plan, the rocket will climb into low-Earth orbit, release nine small satellites, and exercise its upper stage with a series of burns to simulate maneuvers required on future operational Ariane 6 missions. Finally, the upper stage will steer toward a destructive plunge into the atmosphere over the Pacific Ocean and deploy two commercial reentry capsules to test heat shield materials.

Engineers from ESA and ArianeGroup will oversee the launch countdown Tuesday from two main control centers at the Guiana Space Center. Early Tuesday, they will start loading thousands of gallons of super-cold liquid hydrogen and liquid oxygen into the two-stage Ariane 6 rocket.

After a series of final checks, managers will give their "go" for launch and give the command for the rocket to light its Vulcain 2.1 main engine around seven seconds prior to liftoff. Then, two powerful solid rocket boosters will ignite to propel the 183-foot-tall (56-meter) rocket off the launch pad.

This configuration of the Ariane 6, called the Ariane 62, will generate nearly 1.9 million pounds (8,400 kilonewtons) of thrust at full power. A larger version, the Ariane 64 with four strap-on boosters, is tailored for heavier payloads and higher orbits. Ariane 6's boosters are derived from the first stage motor used on Europe's smaller Vega C rocket.

Heading northeast over the Atlantic Ocean, Ariane 6 will jettison its two spent solid boosters nearly two-and-a-half minutes after launch, then release its clamshell-like payload shroud around three-and-a-half minutes into the flight. The hydrogen-fueled Vulcain 2.1 main engine will continue firing until seven-and-a-half minutes.

The Ariane 6 main engine is similar to the engine used on the Ariane 5 rocket, but with a redesigned, easier-to-manufacture nozzle and a 3D-printed gas generator. The Vulcain 2.1 also has a simplified ignition system.

Innovation up top

While the boosters and core stage fall into the Atlantic Ocean, Ariane 6's upper stage will ignite a Vinci engine to accelerate to orbital velocity. This is the part of Ariane 6 that is entirely new, at least in its use on an actual rocket.

The blueprints for the Vinci engine have been around for a quarter-century. The Vinci project has survived several redirections since ESA first approved the engine's development in 1998. The agency initially intended Vinci to become an upgraded upper stage engine for the Ariane 5, then repurposed it for Ariane 6 at the start of that program a decade ago.

The 40,000-pound (180-kilonewton) thrust Vinci engine gives the Ariane 6 several new capabilities lacked by the Ariane 5 rocket. The most fundamental of these upgrades is the Vinci engine's ability to fire up to four times on a single launch, replacing the one-burn upper stage engine flown on Ariane 5.

The restartable Vinci engine will allow Ariane 6 to deploy payloads at different altitudes, or inject satellites directly into high-energy geosynchronous orbits, like SpaceX's Falcon launchers or United Launch Alliance's Atlas V and Vulcan rockets. The upper stage also has an Auxiliary Propulsion Unit (APU)—essentially a miniature second engine—to fulfill several important functions.

These include drawing small amounts of liquid hydrogen and liquid oxygen from the upper stage propellant tanks, heating it up with a gas generator, then injecting the gas back into the tanks to pressurize them. The APU also produces a low level of thrust, enough to settle floating propellant in the upper-stage tanks before each ignition of the Vinci engine, or to make fine adjustments to the rocket's position in space to release payloads in slightly different orbits, a useful feature for deploying large numbers of satellites in Amazon's Kuiper network.

“We have made a lot of innovations between Ariane 6 and Ariane 5, innovation in particular on the upper stage of the launcher, with two brand-new propulsion systems, the reignitable Vinci engine, and also an auxiliary power unit," Huiban said. "This gives Ariane 6 much broader mission capability compared to Ariane 5, but of course, since we introduced an innovative system, we met some difficulties."

Three Vinci engine burns are planned on the inaugural Ariane 6 test flight. The first two firings will put the upper stage into a circular 360-mile-high (580-kilometer) orbit at an inclination of 62 degrees to the equator, setting the stage for separation of nine CubeSats a little more than an hour into the mission. These small spacecraft come from European and US research institutions and will ride alongside a 2-ton inert dummy payload simulating the mass of a heavier primary satellite.

"There are certain (tests) that we cannot carry out on the ground; for example, the behavior of the upper stage in very low gravity," Huiban said. "We cannot eliminate the gravity on the ground, so there are things that we cannot test before flying, so this residual uncertainty and this residual risk must be accepted. I nevertheless perceive in all the teams around me a very high level of confidence."

A third Vinci engine firing more than two-and-a-half hours after launch will de-orbit the upper stage and set it on a course for reentry over the remote South Pacific Ocean. After the burn is complete, the rocket will release two beachball-size reentry capsules from ArianeGroup and The Exploration Company. That will wrap up the Ariane 6 flight sequence.

The Ariane 6's basic version, the Ariane 62, can lift more than 14,300 pounds (6.5 metric tons) of payload into a polar Sun-synchronous orbit, or up to 11,000 pounds (5 metric tons) into a geosynchronous transfer orbit. The heavier Ariane 64 variant can deliver more than 25,000 pounds (11.5 metric tons) to geosynchronous transfer orbit, or about 18,700 pounds (8.5 metric tons) of payload on a trajectory toward the Moon.

A flagship for Europe

Four months after ESA inked the Ariane 6 development contract in 2015, SpaceX landed its first Falcon 9 booster, starting the cycle of rocket recovery and reuse that has proven instrumental in vaulting the Falcon 9 to the top of the launch market. Ariane 6 is one of only a handful of new large or medium-size rockets without reusability in its roadmap, calling into question Europe's ability to compete for commercial launch contracts.

But European governments are aching for independent access to space, and Ariane 6 is poised to provide just that.

At one time, ESA and Arianespace, which operates the Ariane rocket family on a commercial basis, planned a crossover between Ariane 5 and Ariane 6 flights, which were supposed to begin in 2020.Instead, delays with the Ariane 6 rocket meant Europe has gone a year without the ability to put its own large payloads into orbit. In a best-case scenario, assuming Tuesday's test flight goes well, the Ariane 6's first operational launch is scheduled for December, so the new rocket won't start checking off the list of European satellites booked to fly on it for a while longer.

But it gets worse. Europe's light-class Vega C rocket failed on its second flight in 2022, prompting a redesign of the rocket's second stage that will keep Vega-C grounded until the end of this year.

The four-year delay in the Ariane 6 rocket and the grounding of the Vega-C rocket came at the same time that Europe lost access to Russian rockets. Russia's medium-class Soyuz rocket launched 27 times from the Guiana Space Center until officials abandoned the program after Russia's invasion of Ukraine in 2022. If that didn't happen, Soyuz rockets launching from the European spaceport in French Guiana might have been available as a backup for some Ariane and Vega payloads.

Instead, ESA, the European Commission, and Eumetsat—Europe's weather satellite agency—have paid rival SpaceX to the tune of a half-billion dollars to get their satellites out of storage and into orbit. These missions have included ESA's Euclid space telescope and Europe's Galileo navigation satellites. Italy and Spain also turned to SpaceX to launch military satellites that would have likely gone to Arianespace if European rockets were available.

“You don’t want to depend on anybody, and that’s why all the nations that are space-faring nations want their own access to space," Linares said.

Josef Aschbacher, ESA's director general, lamented the situation in a series of statements last year. Last May, he wrote that Europe found itself in an "acute launcher crisis with a (albeit temporary) gap in its own access to space and no real launcher vision beyond 2030."

"The end of the launcher crisis is within reach," Aschbacher posted on X last month. "Now is the time for Europe to support autonomous access to space, which is on the horizon."

Needing a boost

Ideally, European officials would like the Ariane 6 rocket to be as competitive in the commercial launch industry as its predecessor, the Ariane 5, was in the 2000s and 2010s. But Ariane 6 arrives in a vastly different market than Ariane 5 faced in its prime, with dominance by SpaceX and a bevy of new rockets like ULA's Vulcan, Blue Origin's New Glenn, Japan's H3, and emerging competitors like Rocket Lab, Relativity Space, and Firefly Aerospace.

All of these rockets, with the exception of Ariane 6 and H3, are designed with reusability in mind. One could argue that Europe started work on the Ariane 6 rocket at the worst possible time, when rocket reuse was still a novel thought and not yet proven by SpaceX. ESA and ArianeGroup locked themselves into developing the Ariane 6 just before the tide turned on reusable rockets. ULA's Vulcan, which debuted earlier this year, Rocket Lab's Neutron, Relativity's Terran R, and Firefly's Medium Launch Vehicle all entered development after Ariane 6.

However, maybe it's fair to probe Europe's fundamental ambitions in the field of rocketry. Elon Musk, SpaceX's founder and CEO, took a build it and they will come strategy with the Falcon 9. SpaceX bought into the idea that lower launch costs, made possible by reusing rocket hardware, would grow the number of customers who could afford to pay for launch services. While the majority of SpaceX's record number of missions—more than 120 launches in the last 365 days—carry the company's own Starlink Internet satellites, SpaceX is also flying more missions for external customers than ever before.

With its giant new Starship rocket, SpaceX threatens to disrupt the launch industry again. This doesn't seem to bother Tolker-Nielsen. After all, Ariane 6 won't compete to launch many of the payloads that may eventually fly on Starship, such as Starlink satellites, or missions heaving crew and cargo to the Moon or Mars. Likewise, many of the missions assigned to Ariane 6 won't be accessible to SpaceX.

"Honestly, I don’t think Starship will be a game-changer or a real competitor," Tolker-Nielsen said in an interview with Space News. "This huge launcher is designed to fly people to the Moon and Mars. Ariane 6 is perfect for the job if you need to launch a four- or five-ton satellite. Starship will not eradicate Ariane 6 at all."

Arianespace says customers have reserved 30 flights on Ariane 6 rockets, including European institutions, Amazon, Intelsat, Eutelsat, and the Australian telecom company Optus.

“From my point of view, Ariane 6 has already demonstrated its competitiveness with 30 launches in the order book," said Caroline Arnoux, head of the Ariane 6 program at Arianespace.

Sure, Ariane 6 has staying power. It won't be eradicated until a newer, potentially reusable European rocket arrives on the scene. Europe's primary goal for its launcher program is to guarantee independent European access to space. A secondary objective is to field a commercially viable launch vehicle.

Tolker-Nielsen's comments illustrate the way European space officials view the government-funded launcher program. It does not exist to revolutionize space travel. It is there to serve European governments, and ultimately provide services to European citizens. The industrial paradigm also ensures the program's investors (ESA member states) get a return on their investment through industrial contracts, and ultimately jobs.

ESA's policy of geographic return is an inefficient way to manage development of a large project like Ariane 6. Philippe Baptiste, head of the French agency CNES, last year blamed this approach for delays and rising costs on the Ariane 6 program. CNES is also a partner on Ariane 6, with authority over construction of the rocket's launch pad in French Guiana.

In a best-case scenario, Arianespace plans to fly Ariane 6 rockets 10 times a year by 2027. European officials just don't see enough demand to close the business case for reusability, according to Tolker-Nielsen.

"We made the choice of not being reusable with Ariane 6 exactly because of this argument," he told Space News. "Our launch needs are so low that it wouldn’t make sense economically. So, we don’t really need it at this point."

That may change in the 2030s or 2040s, and ESA is partnering with industry on a suborbital reusable rocket demonstrator called Themis that could become the centerpiece for a new orbital rocket. "When we’ll launch frequently in the future, we’ll need reusability for economic reasons," Tolker-Nielsen said. "The second reason to have reusability for a European launcher is sustainability. We must have a circular economy in 10 or 20 years; we need to be sustainable."

When ESA member states decided to develop Ariane 6, officials set a goal of flying the new rocket for half the cost of an Ariane 5, which cost somewhere around 150 million euros per mission. These statements suggested a goal of launching an Ariane 6 rocket for about 75 million euros ($81 million) per flight, somewhat above SpaceX's $67 million selling price for a dedicated Falcon 9 flight.

Last year, Tolker-Nielsen said the Ariane 6 rocket would miss the goal of a 50 percent cost reduction. The Ariane 6's cost per flight will be about 40 percent lower than that of the now-retired Ariane 5, he said.

However, this isn't the whole story. Last November, ESA member states agreed to subsidize ArianeGroup with up to 340 million euros ($368 million) per year to make up financial shortfalls for the production of 27 Ariane 6 rockets that will fly in 2027, 2028, and 2029. Some of these rockets will presumably launch Amazon's Internet satellites. That's up from the 140 million euro ($151 million) annual subsidy in place since 2021.

This didn't sit well with many ESA member states, which have already committed billions of euros to the Ariane 6 program. Apart from the subsidies, Europe has committed to flying at least four missions per year on Ariane 6 rockets beginning in 2026, ensuring ArianeGroup and its subsidiary, Arianespace, a steady flow of business. But European officials were left with little choice but to approve the payments and keep Ariane 6 afloat until a new generation of rockets is ready.

"First and foremost is the guarantee of access to space for our own missions, and those are the missions of the European Space Agency, of the European Union, of Eumetsat, and of all member states," Linares said. "This is the core mission of this launcher."

Listing image: ESA-S. Corvaja